Latching assembly for closure elements



Jan. 29, 1963 R. CHRISTY ETAL LATCHING ASSEMBLY FOR CLOSURE ELEMENTS Filed Sept. 18, 1961 3 Sheets-Sheet l INVENTORS ROLAND CHRISTY KENNETH J. FEWEL Fl' g. /a

A rromvsx Jan. 29, 1963 R. CHRISTY ETAL LATCHING ASSEMBLY FOR CLOSURE ELEMENTS Filed Sept. 18, 1961 3 Sheets-Sheet 2 Fig.3

INV EN TORS ROLAND CHRISTY BY KENNETH J. FEWEL AGE/VT ATTORNEY 3 Sheets-Sheet 3 R. CHRISTY ETAL LATCHING ASSEMBLY FOR CLOSURE ELEMENTS Filed Sept. 18. 1961 Jan. 29, 1963 XiGE/VT 47' OR/VEY v| MT 08 R MW mD N A L O R l- E W E F l m H T E N N E M B ,TO SPRING 70 (m1) United States Patent ce LATCHING ASSEMBLY FOR CLGSURE ELEMENTS Roland Christy, Dallas, and Kenneth J. Fewel, Arlington,

Tern, assignors, by mesne assignments, to the United States of America as represented by the Secretary of the Navy Filed Sept. 18, 1961, Ser. N 139,015 4 Claims. (Cl. 292-216) The present invention relates to locking mechanisms, and in a preferred embodiment to an assembly for maintaining a cover element in closed position when the dimensions of such cover element are such that a plurality of locking units is required to ensure that no premature open ng of the cover will occur.

In certain environments, it is necessary to provide a body member with one or more openings which are formed in the skin or surface thereof in order to permit access at certain times to the interior of the body member, or to allow certain operating functions to be performed through such opening. However, it is further desired that each opening be completely closed during other periods of time. When the dimensions of a particular opening are such that a single latch or lock will suifice to maintain the cover element in closed position, it is usually not too difiicult to achieve the results desired. However, when the opening to be closed by such a cover element extends over a considerable surface area of the body member, then a single latch or lock is not usually adequate, and a number of such units often are necessary. For various reasons, it is sometimes inconvenient or impossible to actuate each such locking unit individually, and Various methods have been devised for changing the status of all of these locks simultaneously, as by means of a cable or other flexible element interconnecting the various units. Due to the inability of such a connecting element to operate without slight variations in its physical dimensions due to the flexible nature thereof, it sometimes happens that all of the interconnected latches do not change their status at exactly the same instant of time. It will be appreciated that under such conditions the cover element will not be free to open if even one of these latches fails to change its status from locked to unlocked position.

The above problem is of particular concern in the field of guided missiles. Certain of these missiles are designed for training purposes, and, for reasons of economy, incorporate means which permits them to be recovered following a training mission and again utilized at some subsequent time. To enable this recovery action to be carried out, such a training missile is often provided with landing gear somewhat similar to that utilized on conventional aircraft, this landing gear being extendable from the missile fuselage prior to the landing operation.

This missile landing gear, when stowed, lies within the missile body, and the opening through which it is selectively extendable remains closed by some door or cover which is customarily hinged to the missile body and usually actuated by a hydraulic cylinder to which fluid pressure is applied just prior to the landing operation. During flight, however, it is essential that this door or cover remain closed and locked, so that the missiles aerodynamic characteristics will not be adversely affected. The size of this door or cover is usually such that several latches are needed to secure it and preclude its inadvertent opening. Some difficulty has been encountered in causing these various latches to operate as a unit, and it will be appreciated that failure of even one latch during the recovery phase will prevent extension of the landing gear and very likely result in destruction of the missile. The present invention accordingly has as one of its objectives .a multiunit locking assembly which is so designed as to Patented .lan. 29, 1%63 revent inadvertent opening of such a cover element, while at the same time ensuring that when an opening of the cover is desired prior to landing, the individual latches will unlock concurrently to permit the appropriate operat ing function to be carried out.

One object of the present invention, therefore, is to provide an improved latching assembly for closure elements.

Another object of the invention is to provide a latching assembly made up of a plurality of individual units which units are concurrently actuated by a control member to ensure that operation of each unit will take place at the same instant of time.

An additional object of the invention is to provide a latching device particularly adaptable to airborne vehicles, such, for example, as a guided missile, in which a portion of the missiles body structure is provided With a selectively closable opening through which certain of the missile components are extendable during flight.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same become better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a somewhat schematic illustration in perspective of one portion of a missile of a type to which the present invention is particularly adaptable;

FIG. la is a schematic View of the latches of PEG. 1 together with means for bringing about their simultaneous operation;

FIG. 2 is a detailed view of a portion of the structure of FIG. 1, illustrating an individual latching unit designed in accordance with the present invention;

FIG. 3 is a view of the structure of FIG. 2 along a path parallel to the longitudinal axis of the missile;

FIGS. 4 and 5, respectively, are detailed views of certain of the components making up the latching unit of FIGS. 2 and 3;

FIG. 6 is a top view of the component of FIG. 5;

FIG. 7 is a side view of the unit of FIGS. 2 and 3, but taken in a direction opposite to that from which the View of FIG. 2 is taken; and

FIG. 8 is a view of the structure of FIG. 3 with the latching mechanism in open rather than in closed position.

Referring now to the drawings, there is illustrated one type of guided missile to which the principles of the present invention are particularly applicable, and which has therefore been chosen as a representative environment in which the latching device to be hereinafter described may be employed. In FIG. 1 certain features of this guided missile are shown in perspective, the body or fuselage of the missile being generally designated by the reference numeral 10. This missile is of a design suitable for use in training personnel in the performance of various launching, guidance and recovery tactics, and it is provided with means for enabling the missile to be recovered intact following such a training mission. Such recovery means includes a main landing gear assembly a portion of which is selectively extendable from the fuselage 19 just prior to landing. This extendable portion includes a pair of landing wheels 12 which are stowed within the missile body lit during flight, and which are actuatable outwardly in conventional fashion by pressurization of a pair of hydraulic cylinders 14. However, the particular constructional features of this landing assembly form no part of the present invention, and are merely set forth as being illustrative of one type of mechanism with which the present concept may be associated.

As hereinabove mentioned, the missile main landing gear assembly is stowed within the missile fuselage during flight. When so stowed, this gear lies Within two chambers respectively closed by a pair of doors 16, these doors 16 being illustrated in FIG. 1 in open position. Although not relevant to the present invention, it might be mentioned that each of the doors 16 is actuated to open position when hydraulic pressure is supplied to a cylinder 18 associated with each door, one end of this cylinder being pivoted on the missile frame. Due to the manner of taking the perspective view of FIG. 1, however, only one of the cylinders 18 is visible in the drawing. The doors 16 are each hinged so as to be rotatable about an axis lying generally parallel to the longitudinal axis of the missile 10. It might be mentioned at this point that the type of missile herein described is launched in such fashion that the landing gear is not utilized for this phase of operation. Consequently, the wheels 12 are retracted prior to such a launch, and the doors 16 closed and locked. Following the flight phase, a signal is transmitted to the missile just prior to landing, and this signal actuates apparatus (only a portion of which is shown) which unlocks the doors 16 and simultaneously pressurizes the cylinders 18 to cause the doors to swing open, following which the wheels 12 are extended into landing position by pressurization of cylinders 14. This apparatus is so designed that system pressure causes the doors 16 to swing open as soon as the locks are placed in condition for such action to occur.

It is apparent that the doors 16 must remain closed at all times during the operational phase of missile flight, and furthermore must be provided with means which will ensure their opening just prior to landing so that the landing gear may be extended. Some difficulty has been encountered both in preventing a premature opening of the doors, as well as in bringing about a positive unlocking thereof at the proper time. The present invention is concerned with the provision of means for overcoming such difficulties.

Referring again to FIG. 1 of the drawings, it will be seen that each of the doors 16 is provided along its lower edge with a plurality of rollers 20 which rollers are designed for respective engagement with a plurality of latching units 22 mounted on the missile framework or fuselage. Due to the manner of taking the perspective view in FIG. 1, only the locking mechanism associated with the left-hand door of the missile is visible, but the righthand door locking assembly, although not seen in FIG. 1, is identical in all respects to the apparatus illustrated, and hence a description of the components set forth in the drawings will suffice as an explanation of the entire system.

The missile of FIG. 1 is constructed with a longitudinal frame portion 24 which extends fore and aft along its under side or belly. The latching mechanism of the present invention is made up, of two assemblies identical in design and operation, with one of the assemblies being carried on the right-hand portion of this body member 24 and the remaining assembly being carried on the lefthand portion of the body member. Each such latch assembly is made up of the components illustrated in outline in FIG. la of the drawings. This assembly of FIG. la incorporates not only a plurality of the latching units 22 (four units are illustrated) but also includes a hydraulic cylinder 26 and a rod 28 which interconnects the latching units. The rod 28 forms an extension of the piston of cylinder 26, so that pressurization of cylinder 26 by any suitable means (not shown) actuates rod 28 longitudinally (or axially) to supply an operating force to each of the latches. The assembly of FIG. la also comprises a spring or other resilient member 30 the purpose of which is to return the rod 28 to neutral position following a depressurization of cylinder 26. It will, of course, be recognized that this cylinder 26 is located within the framework of the missile, even though it is not visible, in FIG. 1 due to the presence of. a bulkhead the purpose of which is to lend structural rigidity to the aircraft.

Each of the latching units 22 is identical in design and operation, and hence a detailed description will be given of one representative unit only. As will be readily recognized from FIG. 1, each latching unit 22 is designed for respective engagement with an associated one of the rollers 20 carried near the lower edge of the doors 16. The latching units 22 are designed for concurrent actuation, so that all of the units will simultaneously change their status from locked to unlocked position when the cylinder 26 of FIG. 1a is pressurized to cause a longitudinal or axial movement of rod 28, which, as above stated, interconnects the latching units in the manner illustrated.

FIG. 2 of the drawings represents a detailed view of one of the latching units 22 shown in FIGS. 1 and 10, viewed from the same general location, that is, laterally or transversely of the missile considered with respect to its longitudinal or fore-and-aft axis. However, for a full understanding of the construction and operation of each latching unit 22, it may be helpful to further consider the showing of FIG. 3, in which the latching unit is viewed from a point along the longitudinal axis of the rod 28 of FIG. 1a. Taken together, the showings of FIGS. 2 and 3 include an angle bracket 32 which is secured to a vertical portion of the missile structural member 24 by means of a pair of bolts 34. The latching assembly now to be described is hinged to this bracket 32 so as to be rotatable through a limited angle about a bolt 36 and thereby allow for any slight misalignment which may initially exist between the latching unit 22 and the door roller 20 with which it is to be associated.

Rotatably mounted on the bracket 32 by the bolt 36 is a latch frame or body made up of a pair of plates 38 and 40, respectively, which are spaced apart from one another but disposed in essentially parallel relationship in a manner perhaps best brought out in FIG. 2 of the drawings. These plates 38 and 40 are respectively provided with oppositely-disposed cutout portions which together form a recess 42 into which recess one of the rollers 20 carried by door 16 is selectively receivable when the doors 16 are in closed position (see the broken line show ing of FIG. 3). In other words, when the doors 16 are closed, each roller 20 enters into a recess 42 formed in the plates 38 and 40 of its associated latching unit 22, so that these elements assume the relative position shown in FIG. 3.

To maintain the roller 20' within recess 42 during flight of the missile of FIG. 1, a latching assembly is provided which includes a keeper 44 disposed intermediate the plates 38 and 49. This keeper 44 is fireely mounted on the rod 28 and is selectively rotatable through a limited angle about the longitudinal axis of the rod. This keeper is illustrated in detail in FIG. 4 of the drawings, and, as shown therein, is of irregular outline. In addition to having an opening through which the, rod 28 extends, it includes a hooked projecting portion 46 which closes the recess 42 formed in plates 38 and 40 when the latching unit 22 is in locked position or, in other words, when the unit has the status illustrated in FIG. 3. It will be noted from this FIG. 3 that the hooked projection 46 of keeper 44, by closing the recess 42, prevents the roller 20 carried on door 16 from leaving the recess and hence maintains the door in the position shown in broken outline.

It has been stated that the keeper 44 is of irregular outline as best shown in FIG. 4 of the drawings. In addition to the hooked projecting portion 46, the keeper 44 includes a linear peripheral portion 48 which lies in a certain rotational or angular location with respect to the pivot rod 28 when the keeper 44 is in closed position (as shown in FIG. 3) and in a difierent rotational or angular location when the keeper has assumed its open position to be described in connection with FIG. 8. Adjacent the peripheral portion 48 of the keeper isa shoulder 50, again best shown in FIG. 4, which is designed to be engaged by a pawl arm 52, this arm, together with a further arm 54, constituting a portion of a pawl assembly 56 (see FIGS.

and 6). This pawl 56 is also depicted in FIGS. 2 and 7, where it is shown as being pivoted by a bolt 58 passing through openings in a bracket 60 which is carried on the outer surface of the plate 38 which forms part of the latch frame or body. As best brought out by FIGS. 2 and 7, the pawl assembly 56 is mounted for limited angular rotation about the pivot point established by bolt 58, this rotation occurring about an axis which lies parallel to the plane defined by the plate 38, and hence perpendicular to the longitudinal axis of the missile as well as to the axis of the rod 23 of FIGS. 1, 1a and 7. This will also be recognized from an inspection of FIG. .3, in which the rod 28 is shown in cross section.

The pawl assembly 56, best shown in FIGS. 5 and 6, has, as previously stated, a pair of arms 52 and 54. The arm 52 is formed with a surfacee or edge portion 62 which is designed for selective engagement with the peripheral portion 48 of the keeper 44 (see FIG. 4) and also intended to engage the shoulder 50 of the keeper to prevent rotation of the latter in a manner which will subsequently become clear. The remaining arm 54 of the pawl assembly 56, however, is designed with a bifurcated end portion 64 made up of a pair of prongs 66 (see especially FIGS. 3 and 6) between which passes the rod 28 described in connection with FIGS. 1 and la. It is intended that a given axial movement of the rod 28 will cause the pawl assembly 56 to pivot about the bolt 58 through a limited angle, and, in order to bring about this result, the rod 28 has securely mounted thereon a screwtype washer or nut 68 (see FIGS. 2 and 7) which has an outer diameter greater than the distance between the prongs 66 of the bifurcated arm 54 and hence engages the arm 54 when sufiicient longitudinal movement of the rod 28 occurs. Such a movement of the rod is depicted in FIG. 7, this displacement being sufficient to move the threaded washer or nut 68 from its position as shown in solid lines to that shown in broken lines. The eifect of this movement of washer 68 is to cause the pawl arm 54 to move from its original position to one which is substantially vertical, as shown by the broken lines. In other words, the arm 54 pivots at 58 to cause the opposite arm 52 of the pawl assembly to rotate clockwise, as indicated by the arrow, and take the position also shown in broken lines.

Assuming that the assembly being described is in locked position (as shown in FIG. 3, for example) the keeper 44 has a rotational position as therein shown. Under these conditions, the shoulder 50 of the keeper in effect hooks over the surface edge portion 62 of the pawl arm 52 As long as the pawl 56 is in its position as shown in solid lines in FIG. 7, no rotation of the keeper 44 can occur due to this engagement between the component portions 50 and 62. However, upon a subsequent axial movement of rod 23 to rotate the pawl 56 about its pivot bolt 58, the surface edge portion 62 of the pawl arm 52 is displaced to a new position as shown in broken lines in FIG. 7, and its engagement with the portions 48 and 50 of keeper 44 is terminated. At this point, the keeper 44 becomes free to rotate about an axis defined by the rod 28 upon which it is mounted, and through which the rod is freely slidable in a direction normal to the plane surface of the keeper.

Attached to the outer extremity of the pawl arm 52 is a spring 70, perhaps best shown in FIG. 7, the remaining end of which is attached to a pin 72 in turn mounted on the upper portion (in the drawings) of the keeper 44 (see also FIG. 4). This spring 70 performs a dual function of maintaining the pawl assembly 56 in its position as shown in solid lines in FIG. 7 and also of maintaining the keeper 44 in a position of maximum counterclockwise rotation as indicated by FIG. 8 except when the keeper 44 is in engagement with the pawl arm 52. Expressed differently, the spring 76 tends to bias the latching assembly to open status until the unit is forced into closed condition by entry of the roller 20 into the recess 42, during which movement the roller 20 contacts the keeper surface portion '74 (FIGS. 4 and 8) and rotates the keeper 44 clockwise about its pivot region 28 to cause a further inclined surface portion 76 of the keeper to frictionally slide over the surface edge 62 of the pawl assembly 56 until the latter snaps over the outer extremity of shoulder 50. This allows the surface edge portion 62 of the pawl to contact the surface portion 48 of the keeper. Following this action, the shoulder 50 maintains the pawl in engagement with the keeper until an axial movement of the rod 28 occurs to rotate the pawl assembly 56 as previously described in connection with FIG. 7.

It is extremely important during preparation for launching of the missile of FIG. 1 to have positive knowledge of the locked condition of each of the latches 22 which maintains the doors I6 closed. The present concept includes means for making a ready determination of this condition by a mere inspection of the exterior of the missile fuselage It). As will be noted in FIG. 3, the pawl arm 52 not only has attached thereto one extremity of the spring element 70, but also has extending in a direction opposite to this spring element 70 a wire or elongated indicator 78 which passes through an opening 79 formed in the frame structural member 24. Since this wire 78 is connected to the arm 52 of the pawl assembly 56 (see FIG. 7) a longitudinal movement of the wire occurs when the pawl 5'6 rotates, and, if the length of the wire is chosen so that the outer extremity thereof is exactly flush with the surface S6) of the structural member 24 when the unit 22 is locked, then it will be appreciated that this wire will extend beyond the fuselage surface when the assembly 22 is unlocked, or, in other words, when the pawl arm 52 is in any rotational position except that shown by the solid lines in FIG. 7. By merely noting whether or not the wire '73 projects outwardly from the surface or skin of the missile (as for example in FIG. 8) an observer can readily determine the status of each of the latching units 22 of FIGS. 1 and la. An important safety feature is thus incroporated in the invention concept.

Referring back to FIG. 1a, it has previously been stated that the spring member 30 is employed merely to return the rod 28 to its original position upon a depressurization of the cylinder 26. Also indicated in FIG. 1a are a number of adjustable elements, such as the turnbuckles 32, which may be employed if desired to enable the length of each of the individual rod portions extending between the respective latching units 22 to be slightly varied in order that operation of each of the latching units will occur simultaneously when the cylinder 26 is pressurized. Once having been set up, however, no further adjustments of the disclosed assembly are normally required except under extremely severe operating conditions.

When the keeper 44 has rotated counterclockwise following a disengagement between its shoulder 50 and the surface edge portion 62 of the pawl assembly 56 (as discussed above in connection with FIG. 7) then the keeper 44 will assume a position relative to the remaining elements of the latching unit as shown in FIG. 8 of the drawings. In such a condition, the hooked projection 46 of the keeper no longer closes the recess 42, and the roller 2t} carried by the door 16 of FIG. 1 is free to leave the recess when cylinder 18 is presurized. Surface 74 of the keeper is urged against the roller 20 by spring 70, and so the keeper rotates as it is permitted to do so by outward movement of the roller from the recess.

It will be appreciated that, by an employment of the means herein disclosed, the latching element (as represented by the keeper 44) is caused to move in a plane which is normal to the direction of movement of the rod 28. This movement of rod 28, however, represents the force applied to actuate the latching mechanism, and, for that reason, it can be stated that the unlocking motion is in a sense applied in a direction normal to the operating plane of the latch itself. Furthermore, each of the latches 22 of FIGS. l'and la is disposed in line, and a single unlocking motion of the rod 28 sufiices to simultaneously change the status of each lock. Although four latches have been illustrated and described as an example, it is obvious that any further number may be utilized according to the particular requirements of the device with which the assembly is to operate.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of theappended claims the invention may be practiced otherwise than as specifically described.

We claim:

1. A latching unit for locking in closed position a cover element designed to overlie when closed an opening in an elongated body member, said cover element being hinged to said body member so as to pivot about an axis lying essentially parallel to the longitudinal axis of the body member and carrying thereon a roller located adja cent the periphery thereof, said latching unit comprising a frame formed of a pair of spaced-apart plates respectively lying in planes essentially perpendicular to the longitudinal axis of said body member, each of said pair of plates being provided with a re-entrant portion to gether defining a recess into which the roller carried onsaid cover element is selectively receivable, a camrned keeper of essentially planar configuration disposed between said pair of plates and rotatable in a plane parallel thereto, said keeper being formed with a hooked projection selectively closing said recess and precluding a movement of said roller therefrom when said unit is in latched condition, a pawl assembly mounted on one of said pair of plates and rotatable through a limited angle about an axis lying perpendicular to the longitudinal axis of said body member, said pawl assembly including an arm positioned to engage a cammed portion of said keeper to maintain the rotational status of the latter when said unit is in latched condition, a slidable rod mounted parallel to the longitudinal axis of said body member and having a washer thereon engaging a further arm of said pawl assembly, means for producing a slidable axial movement of said rod to develop a limited angular rotation of said pawl assembly, whereby the first-mentioned arm of said pawl assemblywill be disengaged from the cammed portion of said keeper so that the latter is free to rotate, and spring means for rotating said keeper followin a disengagement of the cammed portion thereof from said pawl .to cause the hooked projection on said keeper to open the recess in said plates and permit a movement there- 'from of the roller carried by said cover element.

2. A latching unit comprising a frame formed of a pair of spaced-apart body plates lying in parallel relationship,

-a cammed keeper plate disposed between said body plates and rotatable about an axis perpendicular thereto, said pair of body plates each having a re-entrant portion together defining a recess in said frame, said keeper plate having a hooked projection closing the recess formed in said frame when said keeper plate is in a selected rotationalposition about its axis, a pawl carried by one of said body'plates and rotatable about an axis parallel thereto, said pawl including one arm engaging the cammed portion of said keeper plate and maintaining the said selected rotational position of said keeper plate to cause its hooked projection to close said recess, said pawl also including a further arm actuatable to rotate said pawl about its axis and thereby disengage the said one arm thereof from the cammed portion of said keeper plate,

and spring means effective upon a disengagement between said pawl and said keeper plate to rotate the latter about its axis and cause the hooked projection thereof to open the recess formed by the two re-entrant portions in said .pair of body plates.

fore-and-aft axis of the aircraft, a latching mechanism for locking said door in closed position, said latching mechanism including a latch body member mounted within said compartment, said latch body member including a catch selectively actuatable between open and closed positions, the catch when in closed position engaging a projection carried by said door to preclude the latter from opening during the operational phase of aircraft flight, the said catch being selectively actuatable in a plane normal to the said fore-and-aft axis of the aircraft, catch control means including a member movable linearly in a direction parallel to the said aircraft fore-and-aft axis as Well as to the pivot axis of said door, for actuating said catch from closed to open position, and means energizable prior to a landing of said aircraft for linearly moving said member to cause said control means to actuate said catch and thereby disengage the latter from the projection carried by said door, said latching mechanism further including a pawl mounted on said latch body member so as to be rotatable about an axis which extends both normal to the direction of movement of said latch control member and parallel to the plane of rotation of said catch, said catch having a surface portion engaging said pawl when said latch mechanism is in closed position, means mounted on said latch control member for selectively engaging said pawl upon a linear movement of the former to thereby rotate said pawl about its axis and terminate the engagement between said pawl and said catch, and means for urging said latching mechanism to open position following a termination of the engagement between said pawl and said catch.

4. A latching assembly for locking in closed position a cover element designed to overlie when closed a compartment formed in an elongated body member, said cover element being hinged to said body member so as to be rotatable about an axis lying essentially parallel to the longitudinal axis of the body member and carrying thereon a plurality of rollers adjacent the periphery thereof, said latching assembly including a plurality of latching units located within said compartment, said plurality of latching units being equal in number to the number of rollers carried by said cover element and being designed for respective association therewith, each latching unit comprising a frame formed of a pair of spaced-apart plates respectively lying in planes essentially perpendicular to the longitudinal axis of the body member, each of said pair of plates being provided with a re-entrant portion together defining a recess into which the associated roller of the plurality carried on said cover element is selectively receivable, a cammed keeper of essentially planar configuration disposed between said pair of plates and rotatable in a plane parallel thereto, said keeper being formed with a hooked projection selectively closing said recess and precluding a movement therefrom of said roller when said unit is in latched condition, a pawl assembly mounted on one of said pair of plates and rotatable through a limited angle about an axis lying perpendicular to the longitudinal axis of said body member, said pawl assembly including an armpositioned to engage a cammed portion of said keeper to maintain the rotational status of the latter when said unit is in latched condition, a slidable rod mounted within said compartment and disposed in parallel relationship to the longitudinal axis of said body member, said rod carrying thereon a plurality of radiallyextending projection spaced apart therealong and designed for respective association with said plurality of latching units, each of the radially-extending projections carried by said rod engaging a further arm of the pawl assembly included in the latching unit with which the individual radially-extending projection on said rod is as sociated, means for, producing an axial movement of said rod so that the radially-extending projections thereon will each cause a limited angular rotation of the pawl assembly of the latching unit with which it is associated, such limited angular rotation of all of the pawl assemblies being of equal magnitude, whereby the first-mentioned arm of each pawl assembly will be disengaged from the cammed portion of its associated keeper and the latter will be free to rotate, and spring means associated with the keeper of each latching unit for rotating such keeper followim a disengagement of the cammed portion thereof from its associated pawl to cause the hooked projection on such keeper to open the recess in the plates of each latching unit and permit a movement from each latching unit References Cited in the file of this patent UNITED STATES PATENTS Evans Apr. 28, 1942 Van Voorhees May 20, 1958 

2. A LATCHING UNIT COMPRISING A FRAME FORMED OF A PAIR OF SPACED-APART BODY PLATES LYING IN PARALLEL RELATIONSHIP, A CAMMED KEEPER PLATE DISPOSED BETWEEN SAID BODY PLATES AND ROTATABLE ABOUT AN AXIS PERPENDICULAR THERETO, SAID PAIR OF BODY PLATES EACH HAVING A RE-ENTRANT PORTION TOGETHER DEFINING A RECESS IN SAID FRAME, SAID KEEPER PLATE HAVING A HOOKED PROJECTION CLOSING THE RECESS FORMED IN SAID FRAME WHEN SAID KEEPER PLATE IS IN A SELECTED ROTATIONAL POSITION ABOUT ITS AXIS, A PAWL CARRIED BY ONE OF SAID BODY PLATES AND ROTATABLE ABOUT AN AXIS PARALLEL THERETO, SAID PAWL INCLUDING ONE ARM ENGAGING THE CAMMED PORTION OF SAID KEEPER PLATE AND MAINTAINING THE SAID SELECTED ROTATIONAL POSITION OF SAID KEEPER PLATE TO CAUSE IT HOOKED PROJECTION TO CLOSE SAID RECESS, SAID PAWL ALSO INCLUDING A FURTHER ARM ACTUATABLE TO ROTATE SAID PAWL ABOUT ITS AXIS AND THEREBY DISENGAGE THE SAID ONE ARM THEREOF FROM THE CAMMED PORTION OF SAID KEEPER PLATE, AND SPRING MEANS AFFECTIVE UPON A DISENGAGEMENT BETWEEN SAID PAWL AND SAID KEEPER PLATE TO ROTATE THE LATTER ABOUT ITS AXIS AND CAUSE THE HOOKED PROJECTION THEREOF TO OPEN THE RECES FORMED BY THE TWO RE-ENTRANT PORTIONS IN SAID PAIR OF BODY PLATES. 